te')); return $arr; } /* 遍历用户所有主题 * @param $uid 用户ID * @param int $page 页数 * @param int $pagesize 每页记录条数 * @param bool $desc 排序方式 TRUE降序 FALSE升序 * @param string $key 返回的数组用那一列的值作为 key * @param array $col 查询哪些列 */ function thread_tid_find_by_uid($uid, $page = 1, $pagesize = 1000, $desc = TRUE, $key = 'tid', $col = array()) { if (empty($uid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('uid' => $uid), array('tid' => $orderby), $page, $pagesize, $key, $col); return $arr; } // 遍历栏目下tid 支持数组 $fid = array(1,2,3) function thread_tid_find_by_fid($fid, $page = 1, $pagesize = 1000, $desc = TRUE) { if (empty($fid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('fid' => $fid), array('tid' => $orderby), $page, $pagesize, 'tid', array('tid', 'verify_date')); return $arr; } function thread_tid_delete($tid) { if (empty($tid)) return FALSE; $r = thread_tid__delete(array('tid' => $tid)); return $r; } function thread_tid_count() { $n = thread_tid__count(); return $n; } // 统计用户主题数 大数量下严谨使用非主键统计 function thread_uid_count($uid) { $n = thread_tid__count(array('uid' => $uid)); return $n; } // 统计栏目主题数 大数量下严谨使用非主键统计 function thread_fid_count($fid) { $n = thread_tid__count(array('fid' => $fid)); return $n; } ?>javascript - Default function props in functional component - Stack Overflow
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javascript - Default function props in functional component - Stack Overflow

programmeradmin4浏览0评论

So I'm looking through several SO questions and each example pertains to a Class based ponent not a functional ponent.

So I have a Container ListContainer that renders List and I'm passing toggleDrawer(). I'm unable to define toggleDrawer() in the List.defaultProps

ListContainer.jsx

import React, { Component } from 'react';
import List from './List';

class ListContainer extends Component{
  constructor(props){...}
  const toggleDrawer = () => {...}
  render(){
    return(
      <List data={data} toggleDrawer={toggleDrawer}/>
    )
  }
}

...export statement...

List.jsx

import React from 'react';
import PropTypes from 'prop-types';

function List(props){
  const { data, toggleDrawer } = props;
  const openDrawer = () => toggleDrawer();
  const renderListItems = (items) => {//renders a list};

  return(
    <ul>{renderListItems(data)}</ul>
  )
}

List.propTypes = {
  toggleDrawer: PropTypes.func,
};

List.defaultProps = {
  toggleDrawer: <<<<<<<<<<<<<<<< Not sure how to define toggleDrawer() here
}

...export statement...

The problem I'm running into is I've tried using getDefaultProps() and maybe it's not being implemented correctly but that hasn't worked. All the examples I've looked at are using State ponents and so trying to use .bind(this) or this.toggleDrawer.this(bind) or any of the other examples I've tried aren't working either.

What am I missing here? Or would it be better practice to just have toggleDrawer: PropTypes.func.isRequired. That does remove the ESLint error, but I'm not 100% on that function always being required

So I'm looking through several SO questions and each example pertains to a Class based ponent not a functional ponent.

So I have a Container ListContainer that renders List and I'm passing toggleDrawer(). I'm unable to define toggleDrawer() in the List.defaultProps

ListContainer.jsx

import React, { Component } from 'react';
import List from './List';

class ListContainer extends Component{
  constructor(props){...}
  const toggleDrawer = () => {...}
  render(){
    return(
      <List data={data} toggleDrawer={toggleDrawer}/>
    )
  }
}

...export statement...

List.jsx

import React from 'react';
import PropTypes from 'prop-types';

function List(props){
  const { data, toggleDrawer } = props;
  const openDrawer = () => toggleDrawer();
  const renderListItems = (items) => {//renders a list};

  return(
    <ul>{renderListItems(data)}</ul>
  )
}

List.propTypes = {
  toggleDrawer: PropTypes.func,
};

List.defaultProps = {
  toggleDrawer: <<<<<<<<<<<<<<<< Not sure how to define toggleDrawer() here
}

...export statement...

The problem I'm running into is I've tried using getDefaultProps() and maybe it's not being implemented correctly but that hasn't worked. All the examples I've looked at are using State ponents and so trying to use .bind(this) or this.toggleDrawer.this(bind) or any of the other examples I've tried aren't working either.

What am I missing here? Or would it be better practice to just have toggleDrawer: PropTypes.func.isRequired. That does remove the ESLint error, but I'm not 100% on that function always being required

Share Improve this question asked Nov 28, 2017 at 19:28 wsfullerwsfuller 1,8408 gold badges33 silver badges54 bronze badges
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3 Answers 3

Reset to default 9

What you probably want is a noop:

List.defaultProps = { toggleDrawer: () => {} };

The advantage of this is that you can be sure that this.props.toggleDrawer is a function even if no value was specified, which means you can safely call it without checking. Another alternative is to set the default to null, and then check that the prop is a function before calling it:

if(typeof this.props.toggleDrawer === 'function') { /* call function */ }

For the record it doesn't make much sense to define another callback (openDrawer()) which simply calls toggleDrawer. You may as well just call toggleDrawer directly.

Just do:

List.defaultProps = {
  toggleDrawer: function () {
    // enter code here 
  }
}

or arrow functions:

List.defaultProps = {
  toggleDrawer: () => {
    // enter code here 
  }
}

You can also write like this concise style :

List.defaultProps = { 
  toggleDrawer() {} 
};
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